Charge forming device



Oct. 3, 1933. w H. TEETER 1,929,193

CHARGE FORMING DEVICE Original Filed Oct. 15, 1928 Patented Oct. 3, 1933 UNITED STATES.

PATENT OFFICE i ware Application was. 15, 1928, .Serial No a-2 ,511. Renewed Augustzfi, 1932 15 Claims. (Cl. 261'34) This invention relates to a charge forming. device for internal combustion engines and particularly to the type of charge forming device 5 retors, one for each intake port of the engine,

and which cooperate respectively with-a plurality of secondary mixingchambers located adjacent the engine intake ports. These mixing chambers are adapted to receive primary fuel mixture from the primary carburetors and'under certain operating conditions to receive additional air supplied through the branches of an air manifold which supplies air to all of said mixing chambers and is provided with a single air inlet.

Examples of charge forming devices of this character are disclosed in the copending applications of Wilford H. Teeter,Serial No. 221,372, filed September 22, 1927; and Fred E. Aseltine, Serial No. 286,975, filed June 20, 1928, which matured'to Patent 1,819,526 granted August 18, 1931. a In devices of this character heretofore designed, such asthose disclosedinth'e above mentloned applications, various means are provided for regulating the proportions of fuel and air in the mixture under variousoperating conditions, so as to provide the mixture necessary to most satisfactorily operate the engine under all possible conditions of speed and load. These mixture proportioning devices include means for enriching the mixture to some extent on opening movements of the throttle mechanism to provide the power A necessary during the accelerating period. 1 Varione forms of fuel pumps have been provided to supply additional fuel to enrich the a mixture. i These pumps have been only partially satisfactory for various reasons. For'example, mechanically operated pumps require numerous moving partswhich are subject to wear and also add to the manufacturing difficulties, Also mechanically operated pumps are not always effective to supply the quantity :of fuel desired, because of the difficulty in maintaining the delivery conduits full of fuel and also because the pumps do not always supply an amount of fuel proportional to the increase of engine suction on any opening movement of the throttle.

' The present invention is in thenature of an improvement on the devices disclosedin the'above applications and the primary object of the invention'is to provide means for supplying additional fuel to'th'e mixture on openingmovements of the throttle which is simple in construction, uniform in its operation under all conditions of engine operation, and is effective to always supply the desired amount of fuel.- More specifically, it is an object of the invention to provide'a means for supplying additional fuel during the accelerating period which is operable always to'supply an amount of fuel proportional to the increase in engine suction during said period.

According to the present invention these'objects are accomplished by the provision of an auxiliary fuel reservoir supplied with fuel from the main fuel reservoir and communicating with the cylinder of the air valve dash pot so that the level of the fuel in said 'reservoiris raised and lowered as the air valve is opened and closed. A "nozzle for supplying fuel to the mixture passage extends into the said reservoir but terminates at a point normally above the levelof the fuel therein. In the form of the invention herein illustrated, this nozzle-extends to the secondary air passage, but it is obvious that such nozzle I could supply fuel to the primary mixture passages if desired. On opening movement of the air valve, the fuel level in the reservoir is raised so that the lower end of the nozzle is immersed and fuel, is immediately drawn into the secondary air passage by the suction maintained therein at the delivery end of the nozzle. Further objects and'advantages of the present invention will be apparent from the following de scription, reference being had to the accompany ing drawing wherein a preferred embodiment of one form of the present invention is clearly shown. r V

In thedrawingz Fig.1 is a vertical longitudinal section through a charge forming device, in which the present invention is embodied."

Figs. 2 and 3 are sections on the lines 22 and 33 respectively of Fig. 1.

The device disclosed comprisesa 'main air manifold 10 having three outlet branches, the middlebranch 12'being shown herein. Eachv of these branches communicates with one ofthe intake ports 14 of a multi-cylinder engine. These branches are each provided with an attaching flange 16 for securing the manifold to the engine block in the usual manner. Adjacent the inlet of the manifold is provided a flange 18 to which the main carburetor unit is adapted to'be attached, as

shown in Fig. 1.

The carburetor unit comprises amain housing 20 having an attaching flange 22 adapted to be secured to the flange-18 byscrews 24. An air inlet horn 28 issecured, in position 'to register with an openingin the-upper wall of the housing 20, in any suitable way. .A casting '30, having certain dash. pot chambers and fuel passages 7 formed therein, is secured by screws to the lower through a conduit, not shown herein, and the flow of fuel is controlled by a float 3 8 operating in theusual' manner to maintain aconstant level of fuel in the bowl. 1

Fuel fiows from the bowl 32 toga, plurality of. primary fuel nozzles 40, onefof which islocatedin each of the primary mixturepassages 42,"the construction of which will be briefly described here--' inafter. The fuel conduit between the fuel bowl and the nozzle comprises a vertical fuel-passage: 44, communicating at its upper end with a horizontal fuel canal 46,'which connects with each of' the nozzles 40 through orifices 48. Fuel is admitted to thee'passage 44 from the fuel-bowl at lowv speeds througha fixed meteringorifice and at high speeds additional -fuel is admitted through an orifice '52 controlled by a valve 54 in the manner set forthin the above mentioned applications. This valve passes through the hole in the topof the fuel bowl, which isof sufficient size to admitair to the top of-the'fuel bowl so as to maintain atmospheric pressure therein.

Fuel isv lifted from the fuel bowl through the above described passage and nozzles 40 to theprimary mixture passages by thesuction therein. Closing movements-of the throttle cause a reduction in this suctionwhich might permit the fuel column to drop sufficiently to cause a temporary starving of theengine unlessmeans were provided to prevent it, Such means comprise a check valve 56 provided in an enlarged chamber 58 at the junction of channels 44 and 46 and on reduction-of the suction in the mixture passage;

sa-id'valve seats on anannular rib 6O projecting above the bottom of the chamber 58 around the delivery end of the fuel passage .44,-preventing downward flow of fuelthrough said passage.

Each primary fuel nozzle is provided with a main fuel outlet 62in the top of the nozzleand a secondary fuel outlet comprisingtwo orifices 64 and 66, in the vertical wall of said nozzle near the bottom of the primary mixing chamber; At

T relatively high speedsthe mixing chamber suction is enough to lift fuel from the main outlet as well as from the orifices 64 and 66. At idling or low. speed operation under load, however, the suction issufiicient to lift fuel only to some point between the top-of thenozzle and the orifices 64 66, fuel flowing. from these orifices by action of gravity. Each-nozzle is provided with. a re strictedfuel metering orifice 68. w

The primary mixture; passages 42 are parallel to each other and close together; asindicated in Fig. 2,.and when the carburetor is attached to the manifold, these passages are incommunication with conduits conveying the primary mixture to the secondary mixture chambers as fully disclosed in the copending-applications above'referred to. Adjacent thenozzles, the mixture passagesare enlarged to form primary mixing chambers indicated at 43. A single throttle valve 70, which extendsacross'all of the-primary mixture passages controls the flow therethrough and is "provided with grooves 72 which register withsaid passages.

This throttle is operated by means fully described in the above copending applications, and which forms no Lpart of the present: inventionxThe middle primary mixture passage. 42 com mu 1ibers, tube '74 .being associated with the middle the :air, chambers and to the secondary mixing cates with a tube74; fixed in the manifold branch 12 and constituting one of the primary mixture conduits above referred to, which convey the primary mixture to the secondary mixing chambranch of'the manifold and supplying primary mixture to'the secondarymixing chamber formed therein.

Substantially all of the air entering the carburetor -flows through the air horn 28 and is controlled by amain air valve 80, normally held against a seat 82 by a spring 84 received between :the valve and a flange 86 projecting from a sleeve 88-slidably mounted on a stationary sleeve 90' fixed in the housing 20 and serving as a guide 90 sleeve for the air valve stem 92 to which the air valve is secured. When it is desired to choke the carburetor to "facilitate starting of the engine, the flange 86 is adapted to be lifted, by means not shown herein, 95

until the-upperw end of the sleeve 88 is moved into engagement with the valve to hold said valve 'againstits, seat. Suflicient air to carry the starting fuel from'thenozzles to the intake passage through the orifices in the fuel and chambers through a passage 102, which communicates with the inlet of the manifold -10. A manually operable-throttle 104 operated simultaneously with the primary throttle 70 by means of operating connections, fully shown and de-. scribed in the above mentioned applications, controls the passage of air through the passage 102. On opening of "either or both throttle valves, the suction on they air valve 80 is increased and the air valve is opened against the tension of its spring to admit additional airqandincrease the quantity of mixture supplied to the engine. The opening of the valve must be retarded to'some extent to prevent addition of sufiicient airto lean; the mixture. A dash pot is provided to accomplish this result and also to prevent fluttering of the valve which comprises acylinder 110 forming apart of the casting 30 and a piston1l2 secured to the valve stem 92 by -means ;of a flanged coupling 114, being clamped against said coupling member by agnut 116 threadedon the coupling member.. A passage 118 hereinafter more fully-described limits .escape of fuel'from the'dash pot cylinder, and determines the amount of resistance offered by the dash pot to any open-, ing movement of the valve. The specific construction of the piston and cylinder is not material so far as the present invention isconcerned and may be of any conventionaldesign. Communicating with thedash pot cylinder -110 by means ofv thepassage 118, above mentioned, is an auxiliary fuel reservoir 120 which maybe integral with the casting 30, as shown herein, or may be a separate member secured thereto. This reservoir is adapted to be filled with fuel from the main fuel reservoir by means of orifice passage 102, and is adapted to supply fuel theretoduringthe accelerating'period, as will be more minced portion of the reservoir to permitthe III-nape of air therethrough. .-Normally thelower and of the nozzle is above the fuel level maintlflna'l in said extension 126 so that the nozzle is Deflective to supply fuel to :the secondary air homage except under certain operating conditlonamirnormally flowing through the space :130 and ihenoe through the nozzle; However; von movements of the throttle to accelerate the engine, thelevel 'in theextension 126 is raised suflioiently to immerse the lower end of the nozole, whhh willthen immediately supply'fuel to The dash pot piston the secondary air passage. 112 operates to lift the fuel level in the auxiliary reservoir as described; on opening movements of the air valve, the piston .moves downwardly and forces fuel from the dash pot cylinderthrough the passage 11 8 raising the level of the f-nelinthe-mixiliary'reservoir to immerse the lowor end of the nozzle 128 and fuel will then be drown from the said nozzle-by the suction in the airpamage; and since any excess fuel frtcedinto theextension 126 by the dash'pot pistoa'rmrely nms-out through spacel; there is no pumpingof fuel through the nozzle and fuel flows therefrom, at a rate proportional to the increase in suction in the-secondary air passage.

'Ihe effective area of passage 118 may be adjustedby means of avalve 132 which threaded on the tasting 30 :andis provided with a stufling box 1B4'to .prevent'leakage'of fuel around the valve. variably positioning the valve 132, the rosistmce-rofthe dash pot can be adjusted substantially' as desired, but the valveshould always he so as'to permit aflow of fuel through the passage llii-at leastequal to the 4 flow of fuelithro'ugh the nozzle 128, otherwise the flow from-the nozzle might stop before the opening .ofythe throttle stopped because the fuel Jae! in the extension" 126 would belowered bea low the lower end of the nozzle. Air would then flow through the nozzle until the 'fuelrlevel were of fuel displaced by the dash potpistonon maximum opening movement of the air valve. If the re'eervoir'wereof less capacity, any movement of the dash pot piston resulting inthe displacement of a quantity of fuel greaterthan the c a-- pacity' of the auxiliary reservoirwould draw 'air into the dash pot cylinder on return movement of the piston; q

It will belcleai -that the device constructed in accordance withv this invention is always effective to supply an amount offuel to the mixturetpassageon any opening-of the throttle which is proportionalto the increase inisuction'in said .mixture passage, that said device is simple in construction, cheap and easy to manufacture, and has no moving parts whatever to become worn'or get out of adjustment, is always uniform .in'its action and operativetoenrich the mixture subotanially simultaneousb' with any opening movementofthethrottle. i

While the form of embodiment ofthe' present invention as herein disclosed, constitutes :a preferred'form, it is to be understoodgthat other forms might be adopted, :all coming within the scope of the claims which follow. 1

.What is claimed :is as follows:

: .1. .A charge'forming device for internal combustion engines comprising a mixturepassage,

means for supplying fuel andair 'thereto,"a throttle, a :fuel reservoir, 2, fuel nozzle adapted to supp y additional fuel to the mixture passage for acceleration and normally terminating above the fuel level in said reservoir, means voir 'both above and below the fuel level therein and adapted to'supply fuel to said nozzle, an air valve controlling 'adxnission'of air to said I mixture passage, a dash pot controlling" the opening "of said valve andcomprising a. cylinder supplied with-fuel from said reservoir and'a piston secured to the air valve and slidable in said cylinder, and means whereby said piston is effective to raise the fuel level adjacent the nozzle.

2. A charge forming device for internal combustionengines comprising .a mixture passage, means for supplying-fuel and air thereto, a throtin communication with said reser-.

tie, a main fuel reservoir, 9. fuel nozzle adapted to supply additional fuelto the mixture passage foracceleration and normally terminating above the fuel level in said reservoir, an air valve controlling admission of air to the mixture 'passage', a dash pot threfor comprisin'g a piston securedto the valve and a cylinder in which "the piston s'lides an auxiliary fuel reservoirsinto which said nozzle projects, said auxiliary reservoir and cyl inder being supplied with fuel from the main fuel reservoir and a. passage connecting'the cylinder and reservoir whereby movement of the "piston regulates the4liquid level .in saidauxiliary reservoir, andmeans effecting communication be tween theupper part of said auxiliary reservoir above the normal level of the fuel therein and the'upper part of main fuel the fuel leveltherein. y

3. A charge forming device for internal. com bustion engines comprising a mixture passage; means for supplying fuel and air thereto, a throt= tie, a main fuel reservoir, a fuel nozzle adapted to supply additional fuel to'the mixture passage for acceleration and normally terminating above the fuel level in said reservoir; an air valve cona dash pot therefor comprising a piston secured to the valve and a cylinder in which saidpiston slides havingcommunication with the fuel reservoir, an auxiliary reservoir into which said nozzle projects and a passage connecting 'said auxiliary reservoirwith the dash pot cylinder, said auxiliary reservoir having a capacity substantially equalto the maximum volume of liquid displaced by thedash pot piston during opening of the valve, and said "auxiliary reservoir having communication, withsaidqmain reservoir above the fuel level therein. w' ,7 .7

'4. A charge forming device for 'multicylinder engines comprising aplurality of secondarycan buretors, a plurality of primary carburetors sup plying fuel mixture thereto, meansfor supplying fuel andair thereto, ,a secondary air passage supplying air to saidsecondarycarburetors, a

throttle,f means for supplying additional fuel to said :device to enrich the .mixture' for acceleration on openingmovementof the throttleflow of fuel from saidmeans being effected by the suction: in: the "secondary air passage whereby the quantity of fuel supplied on any opening movement of the throttle is proportional to the increase in suction in the secondary air passage reservoir above trolling admission of air to the mixture passage,

The auxiliary fuel reservoir mustuhave a capao'ity atleast'substantially equal to the amount engines comprising vaplurality of secondary carburetors, a plurality of primary carburetors supplying fuel mixture thereto, means for supplying fuel'and airthereto, a secondary air passage supplying ,air to said secondary carburetors, a throttle, means for supplying additional fuel to said device to enrich-the mixture for acceleration on openingmovement of the throttle, said means comprising a singlefuel nozzle communicating with thesecondary airjpassage, the flow offuel therefrom being controlled by the suction maintained adjacent said nozzle.

6. .A- chargeformingadevice. for internal combustion -:engines"c,omprising a secondary. mixing chamber, a primary mixture passage delivering a primary mixture of fuel and air to said sec- 'ondarymixing chamber, means for supplying fuel andairto said primary mixture passage, a throttle, a secondary-air passage supplying air to the secondary mixing chamber, a fuel reser-' voir; a fuel nozzle adapted to supplyadditional i'uel'to the secondaryair, passage to enrich the mixture for acceleration and normally terminate ing above the fuel level in said reservoir, means in communication with said reservoir'both above and below the fuel level therein and adapted to supply fuelgto said nozzle, and means operated by; the suction in thesecondary air'passage on openingof the throttle to. raise the fuel level adjacent the nozzle in [the fuel.

. 7. A chargeforming device for internal combustion, engines comprising a'secondary mixing chamber, a'primary mixture passage delivering a primary mixture of fuel and air to said secondary mixing chamber, means for supplying fuel and -air to said primary mixture passage, a throttle, a secondary. air' passage supplying air to the secondary mixing chamberya fuel reservoir, 'a fuel nozzle adapted to supply additional fuel 'toithefsecondary air passage to enrichthe mixture for acceleration and normally terminating above the fuel level insaid reservoir, means in' passage and means operated bysaid air valve to raise theffuel level adjacent the nozzle until said nozzle isimmer'sedin the fuel.- i

841A charge forming device for internal combustion. engines comprising a: secondary mixing chamber, a, primary mixture passage delivering a primary mixture of fuel and air to said second ary mixing chamberymeans for supplying fuel and air to said I primary mixture passage, a

throttle, a secondary air passage supplying air to the secondary mixing chamber, -a main fuel reservoir, a fuel nozzle adaptedto' supply additional. fuel to the secondary air' passage to en-'', rich the mixture for acceleration and normally terminating above the fuel level in said reservoir,

an'auxiliary reservoir adapted .tosupply' fuel to i" said nozzle normally ineffective, and meansoperated by the suction in'the secondary air. pas

sage to raise the level of fuel in said auxiliaryreservoir .to render the gno zzle' effective, and means effecting communication between the up per part of said auxiliary reservoir :above the normal level of I the fuel therein; and the upper part of said main reservoir abovethe'fuel level therein, ,l .l i

A charge forming device for internal combustion engines comprising, a secondary mixing until said nozzle is immersed and below the fuel level therein and adapted to.

supply'fuel to said nozzle, an air valve controlling admission of air'to said secondary air passage, a dashpot controlling the opening of said air valve comprising a cylinder suppliedwith'fuel from saidreser'voiranda piston secured to the air valveand slidable in said cylinder, andmeans whereby said piston is effective to raise'thefuel level adjacent the nozzle. 1 r '1 r 10. A charge forming device for internal combustion engines comprising a primary'mixture passage, meansfor supplying fuel and air there! to, a secondary mixing chamber intowhichsaid primary mixturepassage delivers a primary'mixture of fuel and air, a mainfuel reservoir, asecondary airpassage for supplying air to'said sec;

. ondary mixing chamber, an air valve controlling I ditions, a passage connecting the dashpotrcyl-i inder and auxiliary reservoir wherebyflopening of the valve regulates the fuel level in the auxiliary reservoir, and means effecting communication between said auxiliary reservoir'above the level of theopening of said nozzle andv the upper part of said'main'reservoir above thefuel level therein.

11. A charge forming device for internal corn- .bustion engines comprisinga mixture passage,

means for supplying fuel and air thereto, a'throttle, a main fuel reservoir, a submergible fuel noz- -zle adapted to supply additional fuel to the mixture passage for acceleration and normally terminating above the-fuel level in said reservoir, an air valve controlling admission. of air to the mix, j

ture passage, a dash pottherefor comprising a piston secured to the valve anda cylinder in which the piston slides, an auxiliary fuel reservoir into which said nozzle projects, an opening in the reservoir adjacent the nozzles to permit overflow of surplus fuel whenthe nozzle is submerged, said auxiliary reservoir and cylinder being sup plied with fuel from the main fuel reservoir and a passage connecting the cylinder and 'rservoir whereby movement of the pistonj regulates the liquid level in said auxiliary reservoir;

12. A' charge forming device for internal combustion engines comprising a mixture passage, means for supplyingfuel and air thereto, a'throttle,= a main fuel reservoir,'-a' submergible fuel nozzle-adapted to supply additional'fuel to the mixture passage for acceleration and normally terminating above the fuel levelin said reservoir, an air valve controlling admission of air-to the mixture passage, an auxiliary fuel reservoir into 1,929,193- voir adjacent the nozzles to permit overflow of surplusfuelfwhen the nozzle is submerged, means for supplying fuel to the auxiliary reservoirfrom the main reservoir, andmeans operated by the air valve for raising the level of'fuel in said auxiliary reservoir following any opening movement-of the throttle to'sub'merge the end of said nozzle.

13. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage delivering a primary mixture of fuel and air to said secondary mixing chamber, means for supplying fuel and air tosaid primary mixture pasasge,-a

throttle, asecondary air passage supplying air to the secondary-mixing chamber, a fuel reservoir,

, a fuel nozzle-adapted to supply additional fuel to the secondary air passage to enrich the mixture for acceleration and normally terminating above the fuel level in said reservoir, and means operated by the suction in the secondary airpassage on opening of the throttle to raise the fuel level adjacent the nozzle until saidnozzle is immersed in the fuel.

14. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage delivering a primary mixture of fuel and air to said secondmixing chamber, means for supplying fuel and air to said primarymixturepassage, a throttle, a secondary air passage supplying air to the secondary mixing chamber, a fuel reservoir, 9.

fuel nozzle adapted to supply additional fuelto the secondary air passage to enrich the mixture for accelerationand normally terminating above secondary air passage supplying air to the sec-v ondary mixing chamber, a fuel reservoir, 2, main fuel nozzle adapted to supply additional fuel to the secondary air passage to enrich the mixture for acceleration and normally terminating above the fuel level in said reservoir, an auxiliary reservoir adapted to supply fuel tosaid nozzle normally ineffective, and means operated by the suction in the secondary air passage to raise the level of fuel in said auxiliary reservoir to render the nozzle effective. I

" WILFORDH. TEETER. 

